intransitive. To construct or develop theories.

intransitive. To form doctrines or theories; to speculate, theorize.

intransitive. To utter propositional speech, or formulate propositional language (see propositional, adj. 2).

intransitive. To lay down scientific propositions; to theorize in a scientific manner.

to try (something)(on) for size: to consider (an idea, theory, etc.) to see whether it fits the facts. Also loosely, to try out or sample. colloquial…